Supplied Buffer Too Large in wire_test.c

The code in wire_test.c does provide an 64*1024 buffer to dns_message_renderbegin(). This might trigger an error in a corner case, where the code is expecting to receive buffers that are not larger than 65536 bytes.

if (result != ISC_R_SUCCESS) {
        INSIST(st.used < 65536);
        dns_compress_rollback(
                msg->cctx, (uint16_t)st.used); 
        *(msg->buffer) = st; /* rollback */    
        msg->buffer->length += msg->reserved;  
        msg->counts[sectionid] += total;
        maybe_clear_ad(msg, sectionid);
        return (result);
}